The three-dimensional architecture of the human lens is directly related to its transparency and ability to change shape during accommodation. By use of the slit-lamp ophthalmoscope and the scanning electron microscope, the study is designed to relate ultrastructural changes in the lens interior, its capsule, or zonular attachments to functional aberrations and the progressive deterioration of the lens due to normal aging, congenital disorders or other disease processes. In addition, these observations are correlated with biochemical changes as determined by protein constituents. Present studies on the human lens include congenital and traumatic ectopia lentis and the effect of aging on the suspensatory apparatus and lens fibers. In addition, we are studying various types of cataracts but are concentrating on the diabetic cataract in the human and in animal model systems (rat and Rhesus monkey). all observations are correlated with clinical findings and biochemical data.